BlsA integrates light and temperature signals into iron metabolism through Fur in the human pathogen Acinetobacter baumanniiBlsA integrates light and temperature signals into iron metabolism through Fur in the human pathogen Acinetobacter baumannii

TUTTOBENE, MARISEL R.; MUSSI, MARÍA ALEJANDRA; TUTTOBENE, MARISEL R.; CRIBB, PAMELA; MUSSI, MARÍA ALEJANDRA; CRIBB, PAMELA

Scientific Reports

Nature Publishing Group

Lugar: Londres; Año: 2018 vol. 8

Light modulates global features of the important human pathogen Acinetobacter baumannii lifestyleincluding metabolism, tolerance to antibiotics and virulence, most of which depend on the short BLUFtypephotoreceptor BlsA. In this work, we show that the ability to circumvent iron defciency is alsomodulated by light at moderate temperatures, and disclose the mechanism of signal transduction byshowing that BlsA antagonizes the functioning of the ferric uptake regulator (Fur) in a temperaturedependentmanner. In fact, we show that BlsA interacts with Fur in the dark at 23°C, while theinteraction is signifcantly weakened under blue light. Moreover, under iron deprived conditions,expression of Fur-regulated Acinetobactin siderophore genes is only induced in the dark in a BlsAdependentmanner. Finally, growth under iron defciency is supported in the dark rather than underblue light at moderate temperatures through BlsA. The data is consistent with a model in which BlsAmight sequester the repressor from the corresponding operator-promoters, allowing Acinetobactingene expression. The photoregulation of iron metabolism is lost at higher temperatures such as30°C, consistent with fading of the BlsA-Fur interaction at this condition. Overall, we provide newunderstanding on the functioning of the widespread Fur regulator as well as short-BLUFs.